In the prior art, there are many anti-loosening devices for threaded fasteners which are adapted to cause jamming of the threads between the nut and bolt when the nut is turned in a loosening direction. For example, it is known to interpose a pair of wedge cams between the nut or bolt head and the workpiece which are operative to prevent unwanted loosening of the fastener.
Heretofore, the wedge cam anti-loosening device has had two major disadvantages. First, removal of the nut requires rotation of the wedge cams in unison with the nut in order to avoid further tightening of the threads; if the nut continues to be forcibly rotated in the loosening direction, the wedge cams have progressively decreasing area of contact with each other and the stresses become increasingly larger until the cams override each other causing the crest of the cams to be damaged. Second, when the nut is tightened the tightening torque is transmitted through the wedge cams which often causes unwanted embedment or sticking of the cam driving teeth to each other, thereby impairing freedom of relative movement of the cams which operates to inhibit loosening of the fastener threads under conditions of vibration and shock.
A general object of this invention is to provide an improved anti-loosening mechanism for threaded fasteners which overcomes the foregoing disadvantages of the prior art.